First:work out the difference (decrease) between the two numbers you are comparing.Decrease = Original Number - New NumberThen: divide the decrease by the original number and multiply the answer by 100.% Decrease = Decrease ÷ Original Number × 100If your answer is a negative number then this is a percentage increase.
If you wish to calculate the percentage increase or decrease of several numbers then we recommend using the first formula. Positive values indicate a percentage increase whereas negative values indicate percentage decrease.